Method and apparatus for preheating and distributing ingots

ABSTRACT

A method and apparatus for preheating and distributing magnesium ingots used in magnesium die casting wherein the heating efficiency is improved thus reducing the energy required to heat the ingots to a temperature varying between 150° C.-350° C. prior to charging into a molten magnesium bath. A housing comprising a ceiling, a floor, side walls extending from the floor to the ceiling for defining a chamber which is divided into at least a storage area and a heating area, and means for moving the ingots from one side to another as well as out to the molten magnesium bath are provided. The apparatus of the invention is adapted to be securely positioned directly atop of a melting furnace whereby the heat generated by said furnace is used to preheat the ingots located within the apparatus prior to charging.

FIELD OF THE INVENTION

The present invention relates generally to the magnesium die casting industry and, more specifically, to methods and apparatus for ultimately improving the overall energy-efficiency of the magnesium die casting process.

BACKGROUND OF THE INVENTION

Generally, transferring semiliquid die casting technology to mass production present more than a few difficulties. Most importantly, there is the difficulty in ensuring that the die casting machinery has a continuous supply of ingots within a suitable temperature range. Such a continuous supply within the suitable temperature range is necessary in order to prevent problems linked to the quality of the die casting. Temperatures and minimum temperature variations are critical as well as other process variable parameters such as metal level in the molten bath and consistent metal pour to meet the unique properties of a magnesium melt operation.

Traditionally, furnaces for melting ingots tend to be extremely inefficient especially when the furnace is designed to handle ingots of various sizes. As a result, excessive heat up energy is required to bring the ingots to the needed homogenizing temperature thus decreasing the overall performance of the furnace. Not only are furnaces inefficient in their use of energy but they also generate high levels of radiant energy which goes to waste.

The ingots must be suitably preheated before being placed in the furnace metal bath. One method used is to simply lay the ingots on top of the furnace and when the operator feels they are ready then place them by hand in the molten bath. This method, and other similar ones, does not allow for heat control and provides no method for the determination of the ingot temperature. Furthermore, the operator is placed in a situation of close contact with the molten bath which is unsafe and unhealthy because, amongst other things, of exposure to the gases being released from the furnace. Also, it is extremely dangerous since requirements that an ingot never be introduced into a molten metal bath until it is above 150° C. is not being followed.

The above are just but a few of the problems associated with magnesium die casting. In light of those problems there exists a need for a method and apparatus which will prove safe and energy efficient in its operation.

SUMMARY OF THE INVENTION

It is a first object of the present invention to provide a safe and energy efficient method and apparatus for preheating and charging ingots into a molten bath.

A specific object of the present invention is to provide an apparatus for preheating ingots to a desired temperature range using the energy generated by the melting furnace in the process.

A further specific object of the present invention is to provide an apparatus for the automatic distribution of ingots.

It is an object of the present invention to provide a method for maintaining the metal bath within a pre-determined volume level and selected temperature preferably within a range of +/−8° C. in order to ensure a consistent quality in the metal.

It is still a further object of the present invention to provide an apparatus for preheating and distributing ingots comprising a housing comprised of a ceiling, a partially opened floor, side walls extending from floor to ceiling defining a chamber which is divided into at least a storage area and a heating area; an opening for loading the ingots into the storage area; means for moving the ingots, one at a time, from the storage area into the heating area; means for moving the ingots located in the heating area to position said ingots for distributing; means for moving the ingots, one at a time, now in a distributing position into an ejector area; means for opening the ejector area and for slidably leading the ingots into a melting furnace; wherein the apparatus is securely positioned atop the melting furnace and whereby the heat generated by a molten bath therein will be used to preheat the ingots located within the apparatus to a suitable temperature range prior to entering said molten bath.

It is yet still a further object of the present invention to provide a method for preheating and distributing ingots comprising the steps of: positioning an apparatus for holding ingots atop a melting furnace; loading the ingots into a storage area of the apparatus; moving the ingots from the storage area into a heating area of the apparatus; moving the ingots within the heating area to position said ingots for distributing; moving the ingots from the heating area into an ejector area; distributing the ingots into the melting furnace when said ingots are within a suitable temperature range.

The foregoing and other features of the present invention are more fully described with reference to the following drawings annexed hereto. Other objects, features and advantages of the present invention will be apparent from the description hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the apparatus of the present invention sitting atop a melting furnace;

FIG. 2 is a diagrammatic perspective view of the apparatus of the present invention sitting atop a melting furnace;

FIG. 3 is a diagrammatic side elevational view of the apparatus of the present invention wherein the heating area is ready to receive an ingot from the storage area;

FIG. 4 is a diagrammatic side elevational view of the apparatus of the present invention wherein an ingot has been moved from the storage area to the heating area;

FIG. 5 is a diagrammatic side elevational view of the apparatus of the present invention wherein the ingots in the heating area are moved up and readied for distributing;

FIG. 6 is a diagrammatic side elevational view of the apparatus of the present invention wherein an ingot is moved from the heating area to the ejector area; and

FIG. 7 is a diagrammatic side elevational view of the apparatus of the present invention wherein an ingot is distributed from the ejector area into the melting furnace.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 and 2 an apparatus 10 for preheating and distributing magnesium ingots used in magnesium die casting is securely positioned atop a melting furnace 12 whereby the heat generated by the molten bath within said furnace 12 is used to preheat the ingots 14, to a suitable temperature range of between 150-350° C., located within the apparatus 10 prior to charging or distributing into said furnace 12.

The apparatus 10 is comprised of a housing 16 which is characterized by its ejector area 28, ceiling 18, floor 20, side walls 22 extending from floor 20 to ceiling 18 for defining a chamber which is divided by divider plate 25 which runs parallel to side walls 22 into at least a storage area 24 and a heating area 26.

The floor 20 is partially opened on the heating area 26 side in order to allow for the heat generated by the melting furnace 12 easier access to the ingots. The ceiling 18 may be adapted with an opening to the storage area 24 for loading the ingots into the apparatus 10. Alternatively, in another embodiment of the present invention loading of the ingots into the apparatus 10 may be achieved through a side wall opening. The heating area 26 is engineered to hold a one-hour supply of ingots as per the requirements of the user as a one-hour queue will ensure proper preheating of the ingots 14.

Referring to FIGS. 3 and 4, there is illustrated the chamber's storage area 24 and heating area 26 of the apparatus 10 ready to move an ingot 14 from said storage area 24 to heating area 26. A hinged finger 30 will ensure that enough space is left in the heating area 26 in order to receive a similar sized ingot from the storage area 24. The present invention also provides for adaptedly positioning support fingers or ingot guides for different size ingots which may be in use depending on the needs of the user, said guides being adaptedly located so as not to interfere with the lifting mechanism and the air circulation within the heating area 26.

In order to ensure that the ingot spends a maximum amount of time in close proximity with the top of the furnace 12 for more efficient preheating, an ingot 14 will be moved as soon as possible from the storage area 24 to the heating area 26 by means of a first pneumatically-operated actuator 32 which actuator 32 is shaped, so as to make its retraction, once the ingot 14 is securely positioned into the heating area 26, safe and easy. Once actuator 32 is back in its original position, as illustrated in FIG. 3, the remaining ingots 14 located in the storage area 24 will fall to a lower position within said storage area 24 and be ready for the next move.

Referring now to FIG. 5, there is shown the ingots in the heating area 26 being lifted into position for distributing once the suitable temperature range has been achieved. To that effect, venting means may be provided in order to ensure that no overheating of the ingots takes place. A pneumatically-operated lift 34 is activated for lifting the ingots located in the heating area 26 to a proper height for distributing, one at a time, from said heating area 26 into the ejector area 28.

Hinged finger 30, which already acts as a marking mechanism in order to ensure that enough space is made available for receiving the next ingot 14 from the storage area 24, will also act as a marking mechanism in order to ensure that proper lift height is achieved. Also, in order to gain access to the ejector area 28, a door 36 is actively opened as the lift 34 gets the ingot 14 in place for distributing into the ejector area 28. In an alternative embodiment of the present invention the apparatus 10 may be adapted so as to move the ingots from top to bottom with an ejector area located in close proximity to the melting furnace, which in some cases may make more sense and may further ensure that the ingots are free of moisture.

Referring to FIG. 6, there is shown the distributing of the ingot 14 from the heating area 26 into the ejector area 28. As discussed above, now that door 36 is opened by the positioning of the ingot via the lift 34, means for moving the lifted and properly positioned ingot 14 from the heating area 26 into the ejector area 28 provided as a second pneumatically-operated activator 38 can be activated.

Now that ingot 14 is properly positioned into the ejector area 28, as illustrated in FIG. 7, the lift 34 will return to its lower position down to hinged finger 30 level while at the same time automatically closing door 36 in order to ensure that, once ejector area 28 is open through bottom opening 40 for slidably releasing and leading the ingot 14 into the melting furnace 12, no unnecessary loss of heat happens in the heating area 26.

It is understood that the apparatus of the present invention is adapted with means for monitoring the temperature of the ingots 14 held in the heating area 26, said means being either a thermocouple or infra red technology.

Furthermore, means for monitoring the molten bath level in the furnace 12 and in combination for automatically activating the whole distributing process of ingots from apparatus 10 to said furnace 12 is provided. A programmable logic controller (PLC) could serve that purpose, for instance.

The operation of the preheating and distributing apparatus 10 of the present invention will be explained hereinafter. To start with, the apparatus 10 will be securely positioned atop the furnace 12 thereby providing for important floor space savings. The ingots 14 will be manually loaded into the storage area 24 before being moved, one at a time, through mechanical means from said storage area 24 to the heating area 26 where said ingots will remain until they achieve a suitable temperature range of 150-350° C., through exposure to heated air generated by the furnace 12, before they are moved within said heating area 26 to a position for distributing, first into the ejector area 28 and eventually from there into the furnace 12.

Other embodiments and uses of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. The specification and examples should be considered exemplary only and do not limit the intended scope of the invention. 

1. An apparatus for preheating and distributing ingots comprising: (a) a housing comprised of a ceiling, a partially opened floor, side walls extending from floor to ceiling defining a chamber which is divided into at least a storage area and a heating area; (b) an opening for loading the ingots into the storage area; (c) means for moving the ingots, one at a time, from the storage area into the heating area; (d) means for moving the ingots located in the heating area to position said ingots for distributing; (e) means for moving the ingots, one at a time, now in a distributing position into an ejector area; (f) means for opening the ejector area and for slidably leading the ingots into a melting furnace; wherein the apparatus is securely positioned atop the melting furnace and whereby the heat generated by a molten bath therein will be used to preheat the ingots located within the apparatus to a suitable temperature range prior to entering said molten bath.
 2. The apparatus according to claim 1, wherein the floor is partially opened on the heating area side for direct contact with the top of the melting furnace and for allowing circulation of the ambient heated air within said apparatus.
 3. The apparatus according to claim 1, wherein the ingots are manually loaded into the storage area.
 4. The apparatus according to claim 1, wherein the means for moving the ingots from the storage area into the heating area is a first pneumatically-operated actuator.
 5. The apparatus according to claim 1, wherein the means for lifting the ingots in the heating area is a pneumatically-operated lift which is connected to mechanically-operated hinged fingers for controlling the distribution of said ingots.
 6. The apparatus according to claim 1, wherein the means for moving the ingots from the heating area into the ejector area is a second pneumatically-operated actuator.
 7. The apparatus according to claim 5, wherein the lift is connected to an ejector area side door said door to open as the lift is lifting the ingots into position for distributing and to close as the lift returns to its lowered position while at the same time the hinged fingers ensure enough space is available for the next ingot to be introduced prior to receiving a further ingot from the storage area.
 8. The apparatus according to claim 1, wherein means for monitoring the temperature of the ingots in the heating area is provided.
 9. The apparatus according to claim 8, wherein the means for monitoring the temperature is a thermocouple.
 10. The apparatus according to claim 8, wherein the means for monitoring the temperature is infrared technology.
 11. The apparatus according to claim 1, wherein means for monitoring a molten bath level in the furnace and in combination for automatically activating the distributing of ingots is provided.
 12. The apparatus according to claim 1, wherein the suitable temperature range of the ingots is between 150° C. to 350° C.
 13. A method for preheating and distributing ingots comprising the steps of: (a) positioning an apparatus for holding ingots atop a melting furnace; (b) loading the ingots into a storage area of the apparatus; (c) moving the ingots from the storage area into a heating area of the apparatus; (d) moving the ingots within the heating area to position said ingots for distributing; (e) moving the ingots from the heating area into an ejector area; (f) distributing the ingots into the melting furnace when said ingots are within a suitable temperature range.
 14. The method of claim 13, wherein the suitable temperature range is between 150° C.-350° C.
 15. The method of claim 13, wherein the ingots are manually loaded into the storage area.
 16. The method of claim 13, wherein the preheating of the ingots is performed in the heating area through a partially opened floor of the apparatus said ingots housed in the heating area wherein heated air generated by the furnace is circulated about the ingots.
 17. The method of claim 13, wherein the ingots contained in the apparatus are advanced therein by pneumatically-operated means. 